In this example, we will create a Port Forwarding entry for DCC (Direct Client-to-Client), a file transfer method which is a sub-protocol of Internet Relay Chat (IRC). This enables IRC peers to exchange files or perform non-relayed chats. Most clients will allow you to use any arbitrary port range, but ports over 5000 are commonly used, and we will use these ports. DCC uses the TCP protocol.

1. Navigate to Firewall |NAT. Port Forward is the default tab, so you should not have to click on that tab. Click on one of the Add buttons to add a port forwarding entry.
2. For Protocol, keep the default of TCP. Destination port range should be set to 5200 for the From port and 5250 for the To port. Set Redirect target IP to the IP address of the computer on which the IRC client is running, and set Redirect target port to 5200. (The end port will be calculated automatically.) All other settings can be kept at their default values. (Note that the default value for Filter rule association is Add associated filter rule, so a corresponding firewall rule will be created.)
3. Enter an appropriate description (such as Port forwarding for DCC) and click on the Save button. On the Port Forwarding page, click on Apply Changes.

You probably want to navigate to Firewall | Rules to confirm that a corresponding WAN firewall rule has been generated. Note that the rule will only allow TCP traffic to pass, so the protocol for the rule matches the protocol set in the port forwarding entry. Assuming the IRC client has been configured correctly, sending files via DCC should now be possible.